This invention relates to a bucket conveyor the buckets of which are pivotally suspended from transverse elements carried by a pair of toothed endless carrying belts made of rubber or synthetic material, running over drive and guide wheels or rollers.
Bucket conveyors are known in which bucket-carrying chains run over sprocket wheels the intertooth spacing of which is equal to that of the opening of the bucket, so that the buckets, when passing around a sprocket wheel, do not undergo a change of shape, and consequently can be of rigid construction. When using endless carrying belts, the spacing of the buckets is reduced relatively to the length of the chord interconnecting two points on a curved part of the conveyor path, which is less than the length of the arc of the curved path between said points. Because of this, in conventional constructions of such bucket conveyors, it is necessary to use flexible buckets made of synthetic material which, on their two sides transverse to the direction of travel, are hinged to one another and suspended from the transverse elements interconnecting the two carrying belts. These flexible buckets are deformed by each conveyor drive or guide roller. Brittle materials cannot be conveyed in such flexible buckets because they are exposed to lateral shear and compression stresses. Moreover, when conveying powderlike materials, such materials can penetrate between the sliding surfaces of the hinges of the articulated parts of the buckets.
Attempts have been made to combine the advantages of both types of bucket conveyors, and to avoid their disadvantages. In the bucket conveyor installation described in German Patent Specification No. 1,150,921 a solution is described in which the conveyor buckets, hinge-suspended from a pair of toothed endless carrying belts, are mutually supported by an intermediate elastic member positioned between them. In this manner each bucket is supported by the conveyor transverse elements only on one of its longitudinal edges transverse to the direction of travel, whilst the other longitudinal edge is supported against the adjoining bucket by means of the elastic member. The elastic support members compensate for the difference between chord and arc length of the curved portions of the conveyor belts passing around the drive and guide rollers so that the buckets are not subjected to a change of shape and can be of rigid construction.
For some applications, however, the use of an additional elastic support member can prove disadvantageous since it must be made of a material other than that of the actual bucket, in particular a flexible elastic material. The elastic material used (for example, rubber) is not resistant to all the conveyed chemicals. Furthermore, the front edge of each conveyor bucket only rises to the level of the elastic support member, so that the capacity of the bucket is correspondingly limited.
An object of the present invention is to provide a bucket conveyor of the aforementioned type which is so constructed that the buckets can be filled to a level higher than that of the transverse connecting elements of the conveyor.
It is a further object to provide conveyor bucket supports which are as resistant to chemicals as all the other parts of the bucket.